President Barack Obama speaks at the White House in Washington on April 17, 2014. Photo Credit: AP / J. Scott Applewhite

WASHINGTON -- President Barack Obama and the first lady will attend the dedication ceremony for the National September 11 Memorial Museum on May 15, a White House official said Friday.

The ceremony will be held seven stories below ground, in front of an exposed slab of the World Trade Center's original slurry wall, and attendance will be limited to invited current and former officials and winners of a lottery for seats, according to the museum.

It will occur on the first day of a six-day dedication period set aside for 9/11 families, survivors, workers and first responders and local residents and business owners before the museum's public opening on May 21.

The museum features two core exhibitions: one to pay tribute to the 2,983 victims of the 9/11 attacks and the 1993 bombing, and another to tell the story of the attacks on the World Trade Center, the Pentagon and in Pennsylvania.